JPH02104628A - High silver grade hard silver alloy - Google Patents

Abstract

PURPOSE:To obtain the title silver alloy usable widely for industry, personal ornaments, etc., by incorporating specific wt.% of nickel, copper and germanium into a silver alloy. CONSTITUTION:A silver alloy is composed of nickel, copper, germanium and silver; where, by weight, 0.01 to 1.0% nickel, 0.01 to 1.0% copper, 0.01 to 1.0% germanium and the balance silver are regulated. The alloy has good workability without losing good characteristics intrinsic in silver. In this way, the hard silver alloy usable widely for industry, personal ornaments, etc., can be obtd.

Description

[Detailed Description of the Invention] <Industrial Application Field> The disclosed technology produces high-grade hard silver alloys that have good workability without losing the inherent good properties of silver and have more stable product properties. It belongs to the technical field of metal composition of silver alloys.

<Prior Art> As is well known, silver is widely used in jewelry, furniture, works of art, etc. due to its elegant and attractive color tone and good workability, and has also been widely used in coins and the like.

Furthermore, it has low electrical resistance, high thermal conductivity, and
Due to its excellent oxidation resistance, it is often used industrially for mechanical devices such as electrical contacts and lead wires, and their parts.

<Problems to be Solved by the Invention> However, although silver has these excellent advantages, it also has low hardness and easily softens over time at medium to low temperatures such as room temperature, even after work hardening treatment. In addition, since the softening temperature is low, there is a tendency for recrystallization to occur easily at low temperatures, resulting in disadvantages such as crystals becoming coarse and coarse.

Therefore, if silver is used as a casting material as it is, it is too soft, and even if it is improved,
At present, it is difficult to obtain stable characteristics.

These inconveniences tend to become more pronounced as the silver quality increases, and therefore, improvements in this point have been widely sought.

<Purpose of the Invention> The purpose of the present invention is to have the basic excellent properties of silver based on the above-mentioned prior art, but to solve problems associated with processing, etc., and to obtain a high-quality silver. It is an object of the present invention to provide an excellent high-silver-grade hard silver alloy that can be fully used industrially and is useful for processing technology applications in the metal packaging industry. <Means/effects for solving the problem> In order to solve the above-mentioned object, the structure of the present invention, which is summarized in the scope of the above-mentioned patent claims, is to solve the above-mentioned problem. Physically and chemically, both qualitatively and quantitatively, based on theory and experiment, it is important to note that nickel is not only extremely effective for grain refinement in alloys, but also useful as a casting material as a raw material. , and is very effective in improving the hardness of the softened material to which it is added, and if its addition is less than 0.01%, no excellent effect can be expected; on the contrary, if it is added in an amount greater than 1.0%, , segregation occurs and stable characteristics are not achieved, and furthermore,
It has been experimentally confirmed that the melting and casting properties are poor, and as a result,
The optimum addition weight ratio range is 0.01 to 1.0%.

Next, regarding copper, its addition has the function of preventing crystal coarsening by increasing the softening temperature.
In addition, it is not only extremely effective for increasing work hardenability, but is also necessary for increasing hardness through precipitation hardening of crystals, and if the weight ratio of addition is less than 0.01%, the effect will be weak; It has been experimentally confirmed that when the content exceeds 1.0%, crystal refinement is suppressed. Therefore, the preferable addition weight ratio range is set to 0.01 to 1.0%.

Finally, regarding germanium, it is not only extremely effective for work hardening at low processing rates, but also extremely effective for improving melting and casting properties, and its addition weight ratio is 0.0
It has been experimentally confirmed that if it is less than 1%, there is no effect, and if it exceeds 1.0%, crystal refinement is suppressed, similar to copper. Therefore, the range of the optimal addition weight ratio is set to 0. 0
It is between 1 and 1.0%.

<Examples> Next, Examples of the present invention are shown in Table 1 below, comparing the additive element components and the compounding ratio of the components with the conventionally known embodiments in terms of weight ratio.

Table 1 There are two types.

For the first to fifth samples of each of the above-mentioned examples and the known example samples, each material was melted in a well-known high frequency heating melting furnace, cast into a shape of t 10xw 50x 1150M, and then cold-cast. t with a rolling roll 5. It was possible to roll it into a predetermined shape.

Next, each example sample and known example sample obtained as described above were subjected to heat treatment and rolling processing as described below to obtain specimens for various characteristic investigations to be used in various test contents described later.

Specimens for investigating various characteristics Note that the numbers in parentheses are not the sample numbers mentioned above.

(1) Softened material: *Sample after heat treatment (2) 10% processed material; *Specimen rolled to t4.5M after heat treatment (3) 50% processed material; *After heat treatment, up to t2.5m Rolled specimen (4) 90% processed material: *After heat treatment, specimen rolled to 5 m (5) Grain size measurement specimen: *After polishing the heat treated specimen, well-known method (6) Test piece for softening temperature measurement; (3) and (4) test pieces, and for the heat treatment marked with * above, were held in an electric furnace at 700°C for 60 minutes and then rapidly cooled in water. It has been processed.

Contents of each test (1) Hardness test Using a micro Vickers hardness tester, the hardness was measured at a load of 1007 and a load holding time of 30 seconds.

(2) Grain Size Measurement After taking a photograph of the structure using an optical microscope, the measurement results were calculated using the following formula.

Crystal grain size = (2 ÷ m) is the number of crystal grains partially included in the photograph.

(3) Softening temperature measurement 50% of each of the above specimens of 50% processed material and 90% processed material
℃, 150℃, 200℃, 250℃, 300℃
, 350° C., and 400° C., and the hardness of the specimens held for 30 minutes and left to cool was measured, and the hardness was determined by analyzing the softening curve.

(4) Measurement of softening over time 37 pieces of each of the above specimens of 50% processed material and 90% processed material were measured.
It was kept in a thermostatic chamber at ℃ for 200 days, and the change in hardness over time was examined.

The results of each of the above tests are shown in Table 2 below.

The above * in Table 2 is an omission of "change after 5th shot."

As can be seen from the test data shown in Table 2 above, the high-grade silver alloy of the invention of this application has improved hardness by 20% to 80% compared to conventional silver alloys, and also has a softening effect. The temperature increased by 70°C to 180°C, and the grain size increased by 9
It was found that the particles were made finer by around 0%, and in addition, no matter what kind of processing was carried out, there was no change over time and the properties were extremely excellent.

<Effects of the Invention> As described above, according to the present invention, in a high-grade hard silver alloy, silver inherently has good color tone, good workability due to low hardness, low electrical resistance, high thermal conductivity, and excellent The hardness can be controlled arbitrarily without losing excellent properties such as oxidation resistance, and if processed to the desired hardness, not only will it not change over time at all, but it also softens easily. It can now be used without change even in high temperature ranges where it could not be used, and because the crystals are fine, extremely stable properties can be obtained even for molded products with complex and minute shapes. Despite having a complex composition ratio, it has good melting and casting properties, making it easy to use the material as a casting material. Therefore, the high-grade hard silver alloy of this invention is suitable for electrical contacts It has an excellent effect that it can be used not only for industrial purposes such as parts for machinery and equipment, but also for accessories and materials for furniture and furnishings.

Claims (1)

[Claims] In a silver alloy consisting of the elements nickel, copper, germanium, and silver, the weight ratio of each of the above elements is 0.
．． A high-grade hard silver alloy comprising: 0.01 to 1.0% copper, 0.01 to 1.0% copper, 0.01 to 1.0% germanium, and the balance silver.